Contagious seed dispersal and shared natural enemies: factors promoting tropical tree diversity?
Informations
- Funding country
Netherlands- Acronym
- -
- URL
- -
- Start date
- 5/15/2007
- End date
- 5/14/2010
- Budget
- 140,608 EUR
Fundings
| Name | Role | Start | End | Amount |
|---|---|---|---|---|
| ALW Innovational Research Incentives Scheme Veni 2006 | Grant | 5/15/2007 | 5/14/2010 | 140,608 EUR |
Organisations
Abstract
Tropical forests are astonishingly rich in tree species. How so many species manage to coexist is an unresolved question in ecology. Seed dispersal and density-dependent mortality are central processes in the major current theories explaining tropical tree diversity. However, theorists usually model dispersal using smooth, leptokurtic functions. This may be inadequate, because most tropical forest tree species are dispersed by frugivorous animals, which tend to provide ?contagious dispersal?: seeds are deposited very patchily and locally, independent of dispersal distance, into multi-species aggregations. Contagiousness of dispersal probably strongly affects seed survival and seedling establishment. Not only is seed survival dependent on the density of conspecific seeds, survival may also be affected indirectly, positively or negatively, by the presence of heterospecific seeds through the action of shared natural enemies (?apparent competition?). If contagious dispersal and apparent competition are commonplace, dispersal and predation may promote tree species coexistence more than is currently thought. I propose to study the occurrence and consequences of contagious dispersal and apparent competition in the tropical moist forest of Barro Colorado Island (BCI), Panama. Aims are to (1) determine to what degree seed dispersal is spatially contagious, (2) investigate the consequences of contagious dispersal for patterns of seed survival and seedling establishment, and (3) evaluate whether contagious dispersal and apparent competition can promote tree species coexistence. I will analyze five unique databases that exist for BCI, including a 19-year record of seed rain into 200 fruit traps, a 5-year record of seedling recruitment in 600 adjacent quadrats, and seedling recruitment in 20,000 quadrats throughout 50 ha of extensively mapped forest. I will do field experiments on seed attractiveness to rodents (the main generalist seed predators), context-dependent seed predation, and seedling establishment. Finally, I will model dispersal and predation to explore how contagiousness and apparent competition affect species diversity.